The Future Gets Wilder: Mertles
In the swampy, hothouse world of 100myh, Turtles rule the earth. The Great Toraton of the Indian subcontinent is the largest living animal on the planet, and smaller relatives are widespread across Africa, Eurasia and the Americas. Herbivores, omnivores and predators of all sizes, they make up the bulk of the visible portions of their respective ecosystems, being nearly as diverse as the Dinosaurs of 165 million years prior. But quite unlike nonavian dinosaurs, turtles managed to conquer the sea, as well. Although modern sea turtles went extinct long ago, a new group has risen to take their place, and the places of many other sea creatures that have been lost to the ages. Mertles are a monophyletic clade of aquatic turtles with a single defining feature; their skulls are fused to their carapaces. In advanced forms, the plastron also connects to the cranium, and the whole body (Minus the lower jaw, eye, flippers, and tail) is covered by a single, sheath-like scale, which melds seamlessly with the beak and provides a streamlined covering for the body. Primitive forms still look fairly turtle-like, but many Mertles have developed very un-turtle-y shapes in response to the demands of their lifestyle. Living in a rigid, bony shell has many advantages for the Mertles. They are protected from predators and are more hydrodynamic, allowing them to move faster underwater without expending so much energy. But there are disadvantages as well. It takes large amounts of calcium to grow and maintain the shells- So much calcium, in fact, that modern seas could not support Mertles. But there are two reasons why they thrive in the 100myh era; The first has to do with the rising sea floor. The same geological processes that drove the seabed up and forced the oceans to flood the continents exposed large deposits of Dolomite, a calcium-rich mineral, which slowly started dissolving into the ocean, increasing the amounts of minerals available to animals in the food chain. The second is that there is less carbon dioxide in the atmosphere than there is today. Less carbon in the atmosphere means less carbonic acid in the ocean. A less acidic ocean means that shelled animals like turtles don't need to expend as much energy to keep their shells healthy and whole, meaning they can devote more energy to things like feeding and reproducing- things that give them and edge in their competitive world. With the emergence of Red Algal Reefs, Mertles underwent an explosion of diversity. Although predatory and herbivorous forms were already beginning to outcompete Gannetwhales, the new habitat gave them an opportunity to exploit a niche that had laid empty for millions of years, since hard corals went extinct in the Anthropocene. The fish didn't have enough time to adapt; the Mertles took over, entering into symbiotic relationships with the algae and adapting in tandem with them. Indeed, the reefs simply could not survive without the turtles, as they provide the indispensible service of pollination. Although other animals like sea slugs, sea spiders, isopods, crabs and fish also pollinate the algae, it is the Mertles- with their specialized beaks curving in ways that perfectly match the floral tubes of the algae- that do the bulk of the pollination in the sea. But there is a problem. The kinds of Mertles that feed on the algae's nectar are largely small animals, only a few inches long, and although the reefs are shallow they frequently bloom some ten meters or more below the surface. That's a long way for a tiny turtle to swim for a breath of air. How do the Mertles get around this difficulty? Some modern turtles have sacs in the walls of their cloacas that extract oxygen from the water, allowing them to stay underwater for much longer periods of time than if they were to breathe only with their lungs. Mertles take this to an extreme. Although many kinds still have functioning lungs and still rise to the surface to breathe, the small reef-dwelling varieties rely entirely on their enlarged cloacal bursae, with only vestigial lungs as a reminder of a byegone era. In all, Mertles are a unique clade of marine organisms uniquely adapted to life underwater, entirely divorced from the land and air. Their presence helps set the stage for the next period in Earth's history, as they outcompete many more familiar species and open the doors for new creatures to fill the void when they finally die out in the next mass extinction. Category:Fandom Category:Reptiles Category:Turtles Category:The Future Is Wild Category:Africa Category:North America Category:South America Category:Europe